Question

Question 1: what is the approximate rate of Colorado River...

Question 1:

what is the approximate rate of Colorado River downcutting (incision) at this location (Latitude: 36.3232 Longitude:  -111.8465) in meters per million years?

Step 1: Fast Travel to these coordinates Latitude:      36.3232 Longitude:  -111.8465

Step 2: Write down the elevation that is on the rim of the Grand Canyon: 1891 m

Step 3: Jump down to the bottom of the Grand Canyon. You can see the avatar way below hanging out in this screenshot, and look at the elevation of the Colorado River: 901 m

Step 4: Determine how deep the Grand Canyon is at this spot? 1891-901 = 990 m

Step 5: Divide the Depth (990 m) by the amount of time it took the Colorado River to reach its current position (4,800,000 - 1,200,000 or 3.6 million years. The unit of the answer should be in meters per million years (m/Ma). The answer would thus be 275 m/Ma.

WHAT DOES THIS MEAN? By itself, its just a number telling you the timescale of downcutting of the Colorado River. Another way of thinking about this is that this rate is the same as 275 mm per thousand years (1/4th of a meter), and it's the same as 1/4th of a millimeter per year.             The Grand Canyon is a spectacular place, and the Colorado River had a lot more work to do than just incise. It also had to transport all of the sediment moved into the river by the side canyon tributary downcutting and also the landsliding of cliff-faced rock that fell into the river. Still, I hope it makes you pause and think about the timescale of canyon cutting

Solved by verified expert